CAVS to MTS Converter
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Supports: CAVS
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Need help?CAVS to MTS Converter
A .cavs file is a bare Chinese AVS (AVS1) video elementary stream; .mts is the file a consumer AVCHD camcorder writes — H.264 video inside an MPEG transport stream. This conversion re-encodes the AVS picture as H.264 and muxes it into that transport stream so Chinese-broadcast archive footage can be dropped into a camcorder-oriented editing timeline. One thing to settle before you start: a genuine raw .cavs carries no audio, so the MTS you get back is a real, playable video that plays silently.
CAVS Format at a Glance
| Property | Value |
|---|---|
| Standard | GB/T 20090.2-2006 (AVS1 video); reissued as IEEE 1857-2013 |
| Promulgated | February 2006 as a Chinese national standard |
| Developed by | AVS Workgroup, China (founded June 2002) |
| Payload | AVS1-P2 coded video, Jizhun profile |
| Container | None — a raw elementary stream with no index or header |
| Audio | None; AVS specifies audio in separate parts of the standard series |
| Typical origin | Chinese digital TV and broadcast equipment, or a stream demuxed out of a .ts |
| Succeeded by | AVS2, published by the IEEE as 1857.4-2018 |
MTS (AVCHD) Format at a Glance
| Property | Value |
|---|---|
| Standard | AVCHD, developed jointly by Sony and Panasonic, introduced 2006 |
| Container | MPEG transport stream |
| Video codec | H.264/MPEG-4 AVC |
| Audio codecs | Dolby AC-3 or uncompressed linear PCM; stereo and 5.1 surround |
| Extension | .mts on the camcorder, .m2ts after import to a computer |
| Best for | Consumer HD camcorder footage and AVCHD-aware editing suites |
| Weak spot | Not a general-purpose delivery format; phones, browsers and web players largely ignore it |
How to Convert CAVS to MTS
- Upload Your CAVS File: Drag and drop your
.cavsonto the page, or click "Add Files" to browse for it. Several streams can be queued and run with the same settings. - Check Video Codec and Quality Preset: Video Codec starts on H.264, which is what AVCHD specifies; MPEG-2 is the main alternative the transport-stream muxer accepts. Under File Compression, Quality Preset starts on "Very High (Recommended)".
- Set Video Resolution or Trim: Video resolution offers Keep original, Resolution Percentage, Preset Resolutions and Width x Height, and Trim takes a start time and a duration if you only want one section of a long capture.
- Convert and Download: Click "Convert" and save the
.mts. No sign-up, no watermark.
What the Quality Preset Sets for H.264
The preset resolves to a constant-rate-factor value on the H.264 encoder — lower means higher quality and a larger file:
| Quality Preset | H.264 CRF | Result |
|---|---|---|
| Highest | 17 | Visually lossless, archival |
| Very High (default) | 18 | Near-lossless; the safe choice for footage you will edit |
| High | 20 | Transparent, no visible artifacts |
| Medium | 23 | Standard delivery quality |
| Low / Very Low | 26 / 28 | Artifacts visible on inspection |
| Lowest | 32 | Heavy artifacts, smallest file |
If you would rather pin a rate than a quality, File Compression also offers Constant Bitrate, Variable Bitrate, Constant Quality and Constraint Quality, plus target-size modes.
Why the Output Plays Silently
AVS1 is a video coding standard, and a .cavs file is the picture stream on its own. There is no audio elementary stream inside it, so there is nothing for the muxer to write into the transport stream and the Audio Codec control has no material to act on. That is not a limitation of this converter — the sound was never in the file you uploaded. It is still sitting in whatever container the video was demuxed out of, which for Chinese AVS broadcast and optical-media content is nearly always an MPEG transport stream or an MP4 holding the video and a separate audio track side by side. Convert that original instead — TS to MTS or MP4 to MTS — and the audio track rides along.
Frequently Asked Questions
Why does my CAVS to MTS file have no sound?
Because the source had none. A raw .cavs is an AVS1 video elementary stream, and AVS1 defines video coding only, so there is no soundtrack packed inside for the converter to carry over. The MTS itself is complete and plays normally — it is simply silent. Convert the container the video came from (TS to MTS, MP4 to MTS) if you need the audio.
The clip definitely played with sound before — where did the audio go?
It stayed behind in the original container. Broadcast AVS content is multiplexed: coded video and a separate coded audio track are interleaved inside a transport stream or MP4. When a tool demuxes that file down to a bare .cavs, it keeps the video elementary stream and discards everything else. The audio is not damaged or hidden; it is in the file you demuxed from.
Will converting AVS to AVCHD improve the quality?
No. This is a lossy-to-lossy re-encode: the H.264 pass cannot restore detail the AVS1 encode already discarded, and a fresh lossy encode is always fractionally softer than its input. A standard-definition broadcast .cavs also stays standard definition — wrapping it as MTS does not make it HD. Choose this conversion for workflow compatibility, not for a quality gain, and leave Quality Preset at Very High to keep the second-generation loss small.
Should I convert CAVS to MTS, or to MP4?
MP4 for almost everyone. MTS/AVCHD earns its place only when a specific camcorder-oriented editor or device expects .mts files. If you just want footage that plays and edits widely, CAVS to MP4 gives you the same H.264 video in a far more portable container. Both outputs are silent when the source is a true video-only .cavs.
What is the difference between .mts and .m2ts?
Naming, mostly. AVCHD camcorders write the clips as .mts on the recording media, and the same streams are conventionally named .m2ts after being imported to a computer or authored to Blu-ray. The underlying data is an MPEG transport stream in both cases. If your software expects the other spelling, CAVS to M2TS writes it directly.
Which video codec does the MTS actually contain?
H.264/MPEG-4 AVC by default, which is the codec AVCHD is built on. MPEG-2 is the main alternative the transport-stream muxer accepts. Your AVS1 source is decoded first and then encoded fresh into the codec you choose — nothing is copied through untouched, so the output bitstream is genuinely H.264 rather than AVS wearing an MTS extension.
Will an AVCHD editor accept the file this produces?
Usually yes: the output is a standard MPEG transport stream with H.264 video, which is what .mts means to most editors. The exception is software that expects a complete AVCHD disc structure — the BDMV/STREAM folder tree a camcorder creates — rather than a loose clip. In that case, import the file as generic footage rather than through the AVCHD import path.
Could my file actually be an AviSynth .avs script instead?
Worth ruling out, because the extensions look alike. An AviSynth .avs file is a short text script telling a frameserver how to process other clips; it holds no picture or sound of its own and cannot be converted into a video. Open the file in a text editor: readable instructions mean AviSynth, and binary data means a genuine Chinese AVS video stream.
How are my files handled, and are they kept private?
Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after the conversion finishes — never shared and never made public. There is no sign-up and no watermark. In our testing, a video-only source muxes into the transport stream cleanly: the finished .mts probes as a single H.264 video track with no audio track present at all, which is exactly what a video-only input should produce.